This invention relates to fluid flow controllers such as relief valves which utilize a diaphragm.
Diaphragms are used in a large variety of fluid flow functions. Diaphragms are found in relief valves, control valves, pressure regulators, shutoff valves, and the like.
A problem with diaphragms is that they can rupture. Diaphragms are typically formed of rubber, which, as a result of high pressures, elevated temperatures, contaminants, and air pollutants such as ozone, can fail in use. This can occur with no warning, with results which can be disastrous and dangerous. For example, if a relief valve fails, a high-pressure gas stream can suddenly be released out through the relief valve.
Another problem with fluid flow controllers, and particularly pressure regulators, is that high pressure fluid can leak into the regulator even when it is shut down. For example, a regulator can be used for reducing fluid pressure from 300 psi to 150 psi. Even if the regulator is shut down, it is possible that fluid can slowly leak into the regulator, eventually reaching a pressure of 300 psi. This can result in a rupture of the diaphragm.
In view of this problem, it is apparent that there is a need for the fluid flow controller having a diaphragm, which, when the diaphragm fails or ruptures, continues to function and does not release the fluid being controlled. Further, there is a need for a fluid flow controller that prevents the diaphragm from rupturing.